CN111766329A

CN111766329A - Method for rapidly identifying recovered and recycled edible oil

Info

Publication number: CN111766329A
Application number: CN202010715314.5A
Authority: CN
Inventors: 刘亚雄; 罗卓雅; 温家欣; 赖宇红; 方继辉
Original assignee: Guangdong Institute For Drug Control (guangdong Institute For Drug Quality
Current assignee: Guangdong Institute For Drug Control (guangdong Institute For Drug Quality
Priority date: 2020-07-23
Filing date: 2020-07-23
Publication date: 2020-10-13
Anticipated expiration: 2040-07-23
Also published as: CN111766329B

Abstract

The invention belongs to the technical field of food detection, and particularly relates to a method for quickly identifying and recycling edible oil. The method adopts drift time ion mobility spectrometry and headspace capillary gas chromatography to detect the diversified volatile chlorinated compounds in the recycled edible oil, thereby identifying the recycled and reused edible oil, even identifying the refined recycled and reused edible oil; and the complex sample pretreatment is not required to be carried out on the sample, the use cost of the instrument is low, the requirement on the level of technical personnel is low, the analysis speed is high, the analysis and detection of one sample can be completed within 30min, the analysis time is greatly shortened, the detection efficiency is greatly improved, and the accuracy is up to 100%.

Description

Method for rapidly identifying recovered and recycled edible oil

Technical Field

The invention belongs to the technical field of food detection. And more particularly, to a method for rapidly identifying recovered and recycled edible oil.

Background

Edible oils produce a variety of toxic and harmful substances during repeated frying, such as 3-chloro-1, 2-propanediol (3-MCPD) esters, 3-MCPD, acrylamide, free fatty acids, trans fatty acids, fatty acid polymers, and the like. Therefore, the identification, recovery and reutilization of the edible oil are of great significance.

At present, the method commonly used for identifying the edible oil in the prior art is mainly a gas chromatography-mass spectrometry combined method, but the method needs complex derivatization pretreatment firstly, and has complex operation. Chinese patent application CN105486744A discloses a method for identifying edible oil, which provides MALDI-MS database of edible oil standard samples; obtaining a mass spectrogram of an edible oil sample to be detected by a MALDI-MS method; analyzing and comparing the mass spectrograms of the edible oil sample to be detected and the edible oil standard sample in the MALDI-MS database by adopting a PCA method to obtain a PCA analysis chart; and identifying the authenticity of the edible oil sample to be detected through the PCA analysis chart, and identifying the edible oil sample to be detected as the edible oil standard sample, the fake edible oil, the adulterated edible oil or the recycled edible oil. According to the method, a large data storage database is required, the result is compared with the database after the sample is detected, the steps are complex, the identification result cannot be obtained immediately, the consumed time is long, and the used mass spectrometry detection instrument is high in use cost and high in requirement on the technical level of operators.

Disclosure of Invention

The invention aims to solve the technical problems that the method for identifying, recovering and recycling edible oil in the prior art needs complex sample pretreatment, expensive instruments and the like, and provides a method for rapidly identifying, recovering and recycling edible oil and having simple operation.

The invention aims to provide a method for rapidly identifying, recovering and recycling edible oil.

The above purpose of the invention is realized by the following technical scheme:

a method for rapidly identifying and recycling edible oil is characterized in that a drift time ion mobility spectrometry and a headspace capillary gas chromatography are combined to detect the recycled and recycled edible oil.

Headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) is a coupled technique of drift time Ion Mobility Spectrometry (IMS) and headspace capillary gas chromatography (HS-GC). After the pretreatment of heating incubation, the headspace components are extracted and injected into the sample inlet through the airtight needle, then the first dimension separation is carried out through the capillary column of the gas chromatography, and the headspace components are ionized by soft chemistry after entering the ionization reaction zone of the IMS. Under the action of electric field force, the ionized products enter the drift region through the periodically opened ion gates and continuously collide with the counter-current neutral drift gas molecules, and the second-dimensional separation of the ion products is achieved by utilizing different inherent collision cross-sectional areas (CCS) of the product ions.

The invention adopts the HS-GC-IMS method, so that the complex sample pretreatment of the sample is not needed, the use cost of the instrument is low, the requirement on the level of technical personnel is low, the analysis speed is high, the analysis and the detection of one sample can be completed within 30min, the analysis time is greatly shortened, and the detection efficiency is greatly improved.

Further, retention time and drift time of headspace capillary gas chromatography were combined with drift time of ion mobility spectrometry with Cl^-The monomer peak was identified as an index. The experimental results show that the compounds are in Cl form^-The monomer peak can be used as an index to quickly identify the recovered and recycled edible oil, and the accuracy is up to 100%.

Furthermore, the method for rapidly identifying, recovering and recycling the edible oil specifically comprises the following steps:

setting instrument parameters of drift time ion mobility spectrometry and headspace capillary gas chromatography, heating a sample at 70-80 ℃ for 20-40 min, carrying out sample injection detection, and analyzing data.

Further, the instrument parameters of the drift-time ion mobility spectrometry include:

detection mode: a negative ion mode; IMS electric field strength: 500 v/cm; drift gas: nitrogen gas with a purity of 99.999%, flow rate: 150 mL/min; length of drift tube: 98 mm; temperature of the drift tube: 45-80 ℃; IMS radioionization source: a tritium source of 300 MBq.

Further, the tritium source is beta radiation with an average radiant energy of 5.68 kilo-electron volts.

Further, the instrument parameters of the headspace capillary gas chromatography comprise:

carrier gas procedure: nitrogen with the purity of 99.999 percent is used as carrier gas; carrier gas procedure: programmed flow rate: the initial carrier gas flow rate is 2-5 mL/min and is kept for 8-12 min; the flow rate of the carrier gas is increased to 35-45 mL/min within 8-10 min, then increased to 130-150 mL/min within 2-5 min, and kept for 8-15 min; column temperature: 50-70 ℃.

Further, the chromatography column of the headspace capillary gas chromatography is a weakly polar SE-54 chromatography column.

Further, the column has a specification of 15m × 0.54mm × 1.0 μm, with 5% diphenyl, 94% dimethyl and 1% vinyl polysiloxane as stationary phases.

Furthermore, the sample injection amount is 100-500 mu L.

Further, the Analytical data is processed using a Laboratory Analytical Viewer software.

The invention has the following beneficial effects:

the invention provides a method for rapidly identifying and recycling edible oil, which detects diversified volatile chlorinated compounds in the recycled edible oil by combining a drift time ion mobility spectrometry and a headspace capillary gas chromatography so as to identify and recycle the edible oil, even identify the refined recycled edible oil; and the complex sample pretreatment is not required to be carried out on the sample, the use cost of the instrument is low, the requirement on the level of technical personnel is low, the analysis speed is high, the analysis and the detection of one sample can be completed within 30min, the analysis time is greatly shortened, the detection efficiency is greatly improved, and the accuracy is up to 100%.

Drawings

FIG. 1 is a HS-GC-IMS spectrum of sample detection in example 1 of the present invention; wherein, FIG. 1-1 is an original graph of an HS-GC-IMS spectrogram; FIG. 1-2 is a partial enlarged view of the HS-GC-IMS spectrum; a-1, B-1,C-1, D-1 and E-1 are monomers Cl of different volatile chlorinated compounds^-Peak, A-2, C-2, E-2 are dimers Cl of different volatile chlorinated compounds^-Peak, A-3, B-3, C-3, D-3, E-3 are trimers of chlorinated compounds of different volatility Cl^-Peaks, A-4, B-4, C-4 are tetramers of chlorinated compounds of different volatility Cl^-Peak(s).

FIG. 2 is a HS-GC-IMS spectrum of the basic factor investigation of the formation of volatile chlorinated compounds of example 2 of the present invention; wherein, FIG. 2-1 is an original graph of an HS-GC-IMS spectrogram; FIG. 2-2 shows HS-GC-IMS spectrum Cl^-Monomer peak extraction plot.

FIG. 3 is a graph showing the results of the effect of sodium chloride content on the formation of volatile chlorinated compounds in example 3 of the present invention; wherein, FIG. 3-1 shows the total Cl of each volatile chloro compound^-A monomer peak signal intensity curve along with the variation of NaCl content; FIG. 3-2 shows each Cl in the HS-GC-IMS spectrum^-Monomer peak extraction plot.

FIG. 4 is a graph showing the results of the effect of water content on the formation of volatile chlorinated compounds in example 4 of the present invention; wherein, FIG. 4-1 shows the total Cl of each volatile chloro compound^-A monomer peak signal intensity curve chart along with the change of water content; FIG. 4-2 shows each Cl in the HS-GC-IMS spectrum^-Monomer peak extraction plot.

FIG. 5 is a graph showing the results of the effect of heating temperature on the formation of volatile chlorinated compounds in example 5 of the present invention; wherein, FIG. 5-1 is the original graph of the HS-GC-IMS spectrogram; FIG. 5-2 shows the total Cl of each volatile chloro compound^-A graph of the variation of the monomer peak signal intensity with the heating temperature; FIGS. 5-3 are HS-GC-IMS spectra for each Cl^-Monomer peak extraction plot.

FIG. 6 is a graph showing the results of the effect of heating time on the formation of volatile chlorinated compounds in example 6 of the present invention; wherein FIG. 6-1 shows the total Cl of each volatile chlorinated compound^-A monomer peak signal intensity curve graph along with heating time; FIG. 6-2 shows each Cl in the HS-GC-IMS spectrum^-Monomer peak extraction plot.

FIG. 7 is a HS-GC-IMS spectrogram of a sample of refined, recycled and recycled edible oil in the detection and identification of refined edible oil in example 7 of the present invention.

FIG. 8 is a drawing showingExample 7 of the present invention detects and identifies Cl in HS-GC-IMS spectrograms of 16 batches of real spot tests for recycling and reusing edible oil samples^-Monomer peak extraction plot.

FIG. 9 shows the effect of different varieties of edible oils on the generation of volatile chlorinated compounds in HS-GC-IMS spectrograms of the present invention, in example 8, each Cl^-Monomer peak extraction plot.

Cl of the invention^-The monomer peak extraction patterns are each experimental group from top to bottom, and 16 Cl detected from left to right^-Monomer signal peaks, representing 16 different volatile chlorinated compounds.

Detailed Description

The invention is further described with reference to the drawings and the following detailed description, which are not intended to limit the invention in any way. The reagents, methods and apparatus employed in the present invention are conventional in the art, unless otherwise indicated.

Among them, FlavourSpec @ HS-GC-IMS instrument (G.A.S., Germany), 60-bit headspace auto-sampler (Combipal, CTC analytical AG, Switzerland), gas-tight needle (1mL, Hamilton, Switzerland).

Unless otherwise indicated, reagents and materials used in the following examples are commercially available.

All samples to be tested were stored at 4 ℃ before use.

Example 1 edible oil detection and identification

1.1 Experimental materials: frying edible oil: and (4) taking the edible oil recovered and recycled by the market spot inspection of the supervision department as the oil sample to be detected.

1.2 Experimental methods:

(1) chromatographic conditions

A chromatographic column: weakly polar SE-54 column (CS-Chromatography Service GmbH, Germany): 15m × 0.54mm × 1.0 μm, 5% diphenyl, 94% dimethyl and 1% vinylpolysiloxane stationary phase;

carrier gas procedure: nitrogen (99.999% purity) as carrier gas; programmed flow rate: the initial carrier gas flow rate is 3mL/min and is kept for 10 min; the flow rate of the carrier gas is increased to 40mL/min within 10min, then increased to 150mL/min within 2min, and kept for 8 min;

column temperature: and 65 ℃.

(2) IMS Condition

Detection mode: a negative ion mode;

IMS electric field strength: 500 v/cm;

drift gas: nitrogen gas with a purity of 99.999%, flow rate: 150 mL/min;

length of drift tube: 98 mm;

temperature of the drift tube: 45 ℃;

IMS radioionization source: 300MBq (beta radiation) with an average radiant energy of 5.68 kev.

(3) Instrument control and data processing

Laboratory Analytical Viewer (LAV) software (version 2.2.1, G.A.S., Germany)

(4) Sample detection: 1g of the oil sample to be detected was placed in a 20mL headspace bottle, heated at 80 ℃ for 30min, and 500. mu.L of headspace air was injected into the GC-IMS through a 1mL heated hermetic needle (85 ℃) for detection.

1.3 results of the experiment are shown in FIG. 1.

The Reactant Ion Peak (RIP) is observed in FIG. 1-1 due to the presence of trace amounts of O in relatively pure nitrogen (99.999% purity)₂Form O₂ ^-Due to O₂Has strong electron affinity, and halogenated compound is in the negative charge reactant ion O₂ ^-Under the assistance of (3) to ionize. Due to the complexity of non-target volatile chlorinated compounds in the fried edible oil, multiple O's may be involved₂ ^-Auxiliary ionization mechanisms including Dissociated Electron Transfer (DET) mechanisms, Resonant Electron Transfer (RET) mechanisms, nucleophilic substitution mechanisms, and cluster-assisted dissociated electron transfer with two energy traps (CADET) mechanisms, among others. While the CADET hypothesis theory can explain the product ions generated by all mechanisms, the main reaction mechanism is as follows:

RXO₂ ^-*→RX^-O₂ ^*(3)

RX^-O₂ ^*→O₂X^-+R (4-a)

wherein R is a radical of a small molecule compound, and X is Cl.

Reactant ion O₂ ^-Can be formed by a Resonant Electron Capture (REC) mechanism, as shown in reaction (1); the long-life intermediate is formed by the reaction of the reactant ion O₂ ^-Electron orbit collisions with RX, as shown in reaction (2); intermediate product RX^-O₂ ^*Is made of RXO₂ ^-*Is formed, as shown in reaction (3), and the reaction rate thereof depends on the ionic dipole force, polarizability and thermodynamic factors of RX; only in the intermediate RXO₂ ^-*On the premise that the internal energy randomization can be performed, the reaction (4) can be performed and X is obtained^-Showing halogen peaks at different degrees of polymerization on the left and right of the RIP, with each having an inherent drift time (fig. 1-2); intermediate RXO₂ ^-*The peak is shown on the right side of RIP, and long-life intermediate RXO₂ ^-*In contrast, due to intermediate product RX^-O₂ ^*The lifetime is too short to be detected in the IMS detection time frame. Thus, the presence of chlorine in volatile chlorinated compounds can be demonstrated with IMS.

At atmospheric pressure, all ions are practically expressed as A^-(H₂O)_n(N₂)_mIn a form aggregated with water and neutral molecules; the degree of agglomeration, i.e. the values of n and m, depend on the temperature and the water content of the drift gas. In order to simplify the expression of the reaction equation, only the core ion is used as the equation expression.

DistinguishingThe chemically volatile chlorinated compounds all produce the same labeled peak in IMS, i.e., Cl^-Therefore, volatile chlorinated compounds with different chemical properties cannot be separated and identified by IMS. But the volatile chlorinated compounds can be separated by gas chromatography, and the invention combines GC retention time and IMS drift time, namely, the invention can be used for identifying and recycling the diversity of the volatile chlorinated compounds in the edible oil. As can be seen from FIGS. 1-2, Cl at different degrees of polymerization versus GC retention time and IMS drift time^-Peaks were distributed on both sides of the RIP, indicating a higher concentration of volatile chlorinated compounds in the recovered, recycled edible oil, with the leftmost column of Cl^-The monomer peak signal is strongest, and the monomer peak signal contains a plurality of monomer signal peaks with different retention times, wherein 16 monomer signal peaks have stronger signals. Therefore, the present invention is represented by a volatile chlorinated compound, and extracts the monomer Cl^-The 16 monomer signal peaks with stronger signals in the peaks are used as evaluation indexes.

EXAMPLE 2 examination of the fundamental factors for the formation of volatile chlorinated Compounds

2.1 Experimental materials: frying edible oil: respectively weighing 100g of palm oil, and respectively adding 5% NaCl and 0% H into each component₂O、0％NaCl+4％H₂O、5％NaCl+4％H₂O、0％NaCl+0％H₂And O, uniformly mixing, sealing by a cover, frying for 4 hours at the temperature of 160 ℃ by using an electric frying machine, and cooling to obtain an oil sample to be detected.

2.2 Experimental methods: HS-GC-IMS data of each group of oil samples to be tested were respectively determined by the experimental method 1.2 in reference example 1, and Cl was extracted^-Monomer peak data were compared and the results are shown in figure 2.

2.3 Experimental results: as can be seen, 5% NaCl + 0% H₂O、0％NaCl+4％H₂O、 5％NaCl+4％H₂O、0％NaCl+0％H₂Cl of each group O^-No obvious signal is generated in the monomer peak, and no volatile chloro compound can be detected. Therefore, the chloride ions and the water are basic factors for forming volatile chlorinated compounds, and the chloride ions can react with small molecular compounds to form corresponding volatile compounds only after being dissociated from the sodium chloride in the water environmentA chlorinated compound.

EXAMPLE 3 Effect of sodium chloride content on volatile chloro Compound formation

3.1 Experimental materials: frying edible oil: respectively weighing 100g of palm oil, and adding 1%, 2%, 5%, 10%, 20% NaCl and 15% H into each component₂And O, uniformly mixing, sealing by a cover, frying for 4 hours at the temperature of 160 ℃ by using an electric frying machine, and cooling to obtain an oil sample to be detected.

3.2 Experimental methods: HS-GC-IMS data of each group of oil samples to be tested were respectively determined by the experimental method 1.2 in reference example 1, and Cl was extracted^-Monomer peak data were compared and the results are shown in figure 3.

3.3 Experimental results: as can be seen, the measured values of volatile chlorinated compounds increase rapidly and then flatten out as the NaCl concentration increases from 1% to 5%. This is probably because, at first, the higher the content of sodium chloride, the more chloride ions are provided for the formation of volatile chlorinated compounds, and trace elements such as iron and copper in NaCl are also common oxidants in heating reactions of edible oils, which helps to increase the content of small molecular compounds in frying oils, thereby forming volatile chlorinated compounds; however, with further increase in NaCl concentration (from 5% to 20%), the trend of the measured values of the volatile chlorinated compounds tends to be moderate, which can be explained as: the rate of formation of small molecule compounds is greater than the rate of their reaction with chloride ions to volatile chlorinated compounds, with the result that not only is the concentration of volatile chlorine compounds evaporated in the headspace of the static headspace bottle diluted, but O is consumed in excess during IMS ionization₂ ^-Thereby inhibiting ionization of the volatile chlorine compounds.

EXAMPLE 4 Effect of Water content on volatile chloro Compound formation

Water is one of the important factors in the frying process, and it is therefore necessary to investigate the effect of water content on the generation of volatile chlorides during the frying process. The chemical changes in the edible oil after frying are mainly caused by hydrolysis and oxidation. The hydrolysate of the fried edible oil comprises monoglyceride, triglyceride, free fatty acid and glycerol, and the headspace sampling mode cannot be detected because the hydrolysate is not volatile. However, the oxidation products of the fried edible oil contain abundant volatile small molecule compounds, including aldehydes, ketones, acids, alcohols, etc., which can react with chloride ions to produce volatile chlorinated compounds, which can be detected by headspace sampling. Thus, the effect of water on volatile chlorinated compounds is primarily due to the effect of water on the oxidation of edible oils.

4.1 Experimental materials: frying edible oil: respectively weighing 100g of palm oil, and respectively adding 5% of NaCl and 1%, 2%, 4%, 8%, 12% and 15% of H into each component₂And O, uniformly mixing, sealing by a cover, frying for 4 hours at the temperature of 160 ℃ by using an electric frying machine, and cooling to obtain an oil sample to be detected.

4.2 Experimental methods: HS-GC-IMS data of each group of oil samples to be tested were respectively determined by the experimental method 1.2 in reference example 1, and Cl was extracted^-Monomer peak data were compared and the results are shown in figure 4.

4.3 Experimental results: the effect of water on the formation of volatile chlorinated compounds is three-stage. In the first stage, the formation of volatile chlorinated compounds is slowly increased, in the free radical reaction of the frying oxidation of the edible oil, the lower water content (1-2%) can form hydrogen bonds with triglyceride hydroperoxide to protect the triglyceride hydroperoxide from oxidative decomposition, and simultaneously, the catalytic oxidation capability of trace metal elements after hydration is inhibited, so that the initial oxidation rate of the frying oil can be reduced; in the second phase, the formation of volatile chlorinated compounds increases rapidly, the higher water content (from 2% to 8%) increases the solubility of oxygen, and also swells the fat macromolecules so as to expose more oxidation sites, accelerating the oxidation of the frying oil; in the third stage, the tendency of the formation of volatile chlorinated compounds tends to be moderate again, since the large amount of water (from 8% to 15%) dilutes the concentration of the catalyst and of the reactants.

EXAMPLE 5 Effect of heating temperature on the formation of volatile chlorinated Compounds

5.1 Experimental materials: frying edible oil: respectively weighing 100g of palm oil, and adding 5% NaCl and 15% H into each component₂O, mixing, sealing with a cover, and frying with electric frying machine at 100, 160, 180, and 2 respectivelyFrying at 00 deg.C for 1 hr, and cooling to obtain oil sample.

5.2 Experimental methods: HS-GC-IMS data of each group of oil samples to be tested were respectively determined by the experimental method 1.2 in reference example 1, and Cl was extracted^-Monomer peak data were compared and the results are shown in figure 5.

5.3 Experimental results: as can be seen, the degree of oxidation of the edible oil is largely dependent on the increase in temperature. It is clear that the content of small molecule compounds generated by oxidation during the frying process of the edible oil (as shown in the rectangular marked area of fig. 5-1) increases sharply with the increase of the temperature; theoretically, the amount of volatile chlorinated compounds should also increase rapidly, but the test results show that the highest value of chlorinated compounds is measured after frying at 160 ℃ and the value of chlorinated compounds is gradually decreased when the frying temperature is increased, as shown in fig. 5-2. This phenomenon can be explained by 3.3 principles.

EXAMPLE 6 Effect of heating time on volatile chloro Compound formation

6.1 Experimental materials: frying edible oil: respectively weighing 100g of palm oil, and adding 5% NaCl and 4% H into each component₂And O, uniformly mixing, sealing by a cover, frying for 0, 1,2, 3, 4, 8, 18, 24, 40 and 48 hours at the temperature of 160 ℃ by using an electric frying machine, and cooling to obtain the oil sample to be detected.

6.2 Experimental methods: HS-GC-IMS data of each group of oil samples to be tested were respectively determined by the experimental method 1.2 in reference example 1, and Cl was extracted^-Monomer peak data were compared and the results are shown in figure 6.

6.3 Experimental results: as can be seen, when the edible oil is heated for 0h, Cl is present^-No obvious signal response exists at the monomer peak, which indicates that the fresh edible oil which is not heated and used does not contain volatile chlorinated compounds and can be completely distinguished from the repeated and recycled edible oil; the highest measured volatile chlorinated compound value was obtained when the edible oil was heated for 6 hours, and the measured chlorinated compound value gradually decreased after increasing the time, as shown in fig. 6-1. This phenomenon can be explained by the 3.3 principle.

Example 7 detection and identification of edible oil for refining recovery and recycling

7.1 Experimental materials:

(1) recovering and recycling the edible oil: taking the edible oil recovered and recycled in 16 batches in the market spot inspection by a supervision department as an oil sample to be detected;

(2) refining, recovering and recycling the edible oil: randomly selecting 1 recovered and recycled edible oil sample, respectively mixing the edible oil sample with 30% sodium hydroxide, reacting for 10min at 75 ℃, washing for 3min by using 5-6% distilled water, centrifuging for 5min at 4000r/min, vacuumizing to 0.1Mpa at 105 ℃ until the oil becomes transparent, adding activated clay with the mass of 3% of that of the oil sample, decoloring for 30min at 110 ℃, and finally deodorizing for 30min at 220 ℃ under 0.1Mpa to obtain refined and recycled edible oil serving as the oil sample to be detected. The acid value, peroxide value and polar component of the oil sample to be measured all meet the relevant regulations.

7.2 Experimental methods: HS-GC-IMS data of each group of oil samples to be tested were respectively determined by the experimental method 1.2 in reference example 1, and Cl was extracted^-The monomer peak data were compared and the results are shown in FIGS. 7-8.

7.3 Experimental results: as can be seen from the figure, although the content of the small molecular compounds in the recovered and recycled edible oil is obviously reduced after refining, the reduction of the small molecular compounds inevitably reduces the dilution of the small molecular compounds on the target substances and the inhibition of the ionization of the volatile chlorinated compounds; cl^-The appearance of the monomer peak demonstrates that the volatile chlorinated compounds are not completely removed during the refining process, and therefore, the method of the present invention can also be used to identify refined, recovered, repeated edible oils. The reason is that the food oil introduces sodium chloride and water in the using process, so that volatile chlorinated compounds are continuously generated in the refining high-temperature deodorization process and can be sensitively detected by an IMS system.

At the same time, 16 batches of real spot checks of the invention for the recovery of edible oil, Cl^-The monomer peaks all had signal responses of different intensities, which confirmed that they were recovered, repeated edible oils with 100% accuracy, as shown in fig. 8.

EXAMPLE 8 Effect of different varieties of edible oils on volatile chlorinated Compound production

8.1 Experimental materials: frying foodOil: respectively weighing 100g of sunflower seed oil, rice oil, linseed oil, peanut oil, blend oil, grape seed oil, soybean oil, corn oil, rapeseed oil and palm oil, and respectively adding 5% of NaCl and 5% of H into each component₂And O, uniformly mixing, sealing by a cover, frying for 2 hours at the temperature of 160 ℃ by using an electric frying machine, and cooling to obtain an oil sample to be detected.

8.2 Experimental methods: HS-GC-IMS data of each group of oil samples to be tested were respectively determined by the experimental method 1.2 in reference example 1, and Cl was extracted^-Monomer peak data were compared and the results are shown in figure 9.

8.3 Experimental results: as can be seen, the effect of different varieties of edible oil is different, wherein the content of volatile chlorinated compounds in palm oil is the highest.

In conclusion, the HS-GC-IMS is used for detecting volatile target substances with ultrahigh sensitivity for the first time, the diversity of the volatile chlorinated compounds in the edible oil which are recovered and reused is proved, experiments show that the generation of the volatile chlorinated compounds can be obviously influenced by the sodium chloride content, the water content, the heating temperature and the heating time, and the volatile chlorinated compounds can not be removed in the refining process. Therefore, the volatile chlorinated compounds can be used as indexes for identifying and recycling the edible oil, even the refined edible oil. The method detects the recycled and recycled edible oil which is actually sampled and inspected for 16 batches, and the accuracy rate reaches 100%.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, and simplifications are intended to be included in the scope of the present invention.

Claims

1. The method for rapidly identifying the recovered and recycled edible oil is characterized by detecting the recovered and recycled edible oil by combining a drift time ion mobility spectrometry and a headspace capillary gas chromatography.

2. The method of claim 1, wherein the retention time and drift time of the headspace capillary gas chromatography are combined with the drift time of the drift time ion mobility spectrometry as Cl^-The monomer peak was identified as an index.

3. The method according to claim 1 or 2, characterized in that it comprises in particular the steps of:

4. The method of claim 3, wherein the instrument parameters of drift-time ion mobility spectrometry comprise:

detection mode: a negative ion mode; IMS electric field strength: 500 v/cm; drift gas: nitrogen gas with a purity of 99.999%, flow rate: 150-200 mL/min; length of drift tube: 98 mm; temperature of the drift tube: 45-80 ℃; IMS radioionization source: a tritium source of 300 MBq.

5. The method of claim 4, wherein the tritium source is beta radiation and the mean radiant energy is 5.68 keV.

6. The method of claim 3, wherein the instrument parameters for headspace capillary gas chromatography comprise:

carrier gas procedure: nitrogen with the purity of 99.999 percent is used as carrier gas; programmed flow rate: the initial carrier gas flow rate is 2-5 mL/min and is kept for 8-12 min; the flow rate of the carrier gas is increased to 35-45 mL/min within 8-10 min, then increased to 130-150 mL/min within 2-5 min, and kept for 8-15 min; column temperature: 50-70 ℃.

7. The method of claim 3, wherein the chromatography column of headspace capillary gas chromatography is a weakly polar SE-54 chromatography column.

8. The method of claim 7, wherein the chromatography column has a size of 15m x 0.54mm x 1.0 μm and comprises 5% diphenyl, 94% dimethyl and 1% vinyl polysiloxane as stationary phases.

9. The method according to claim 3, wherein the amount of the sample is 100-500 μ L.

10. The method of claim 3, wherein the analytical data is processed using a Laboratory analytical viewer software.